Freshwater reservoir beneath Great Salt Lake may extend across the lake.

Researchers reported an airborne electromagnetic survey detected a layer of fresh water beneath a 10-square-mile area of Great Salt Lake, with sediments showing fresh water from about 100 meters down to as much as 2.5 miles deep. The authors said additional surveys and analysis are needed to confirm how widely the reservoir extends.

Scientists reported a layer of fresh water beneath parts of Utah's Great Salt Lake following a focused airborne survey. The survey covered about 10 square miles along the lake's eastern margin where reed-covered mounds had appeared on a dried patch. Researchers say the mapped freshwater sat in sediments from roughly 100 meters down to as much as 2.5 miles in places. The finding was published in Scientific Reports and the team said broader surveys are required to confirm the reservoir's full extent. Key findings: - An airborne electromagnetic survey over a 10-square-mile area detected signals consistent with fresh water in lake sediments. - The mapped freshwater was reported at depths ranging from about 330 feet (100 m) to as deep as 2.5 miles (4 km) beneath the survey area. - Reed-covered mounds on a dried section of the lake bed provided initial evidence that groundwater was present and reaching the surface. - Magnetic data from the survey indicated watertight "basement" rocks below the freshwater and faults that may explain abrupt depth changes. - The study authors reported that, if the reservoir extends broadly, the groundwater could be relevant to wetting exposed lake bed and to local water availability, but they emphasized further study is needed. Summary: The reported discovery points to a substantial freshwater layer beneath the surveyed portion of Great Salt Lake and could have implications for dust from exposed lake bed and regional water resources. The researchers said expanded airborne surveys and additional analyses are needed to determine the reservoir's size, structure and boundaries; undetermined at this time.